238 
PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
in any real or alleged herbivorous or mixed-feeding animal. The anatomy of Chiromys 
added, in that year, the interesting and instructive exception (admitting the Aye-aye to 
be a mixed feeder). If it had been contended that the lower-placed condyle shown in 
Plagiaulax, and deducible in Thylacoleo, was absolute, independently of other characters 
and considerations, in demonstrating the carnivorous nature of these marsupials, the dis- 
covery of the structure of the mandible of the Aye-aye would have placed a seeming 
objection and a feasible argument in the hands of an advocate of the non-carnivorous 
character of Thylacoleo and Plagiaulax. If it were proved that the Aye-aye is a vege- 
table feeder, not to say herbivorous, the same advantage would be his who had inter- 
preted the fossil remains of Thylacoleo and Plagiaulax , notwithstanding the low-placed 
condyle, as those of vegetarians, having their nearest affinities “ to the marsupial her- 
bivores, such as Halmaturus , Hypsiprymnus, and Phascolarctus ” * * * § . 
But the only testimony we have at present of the natural food of Chiromys shows it 
to be “ carnivorous ” in the sense of subsisting on the flesh or insect-tissues of wood-boring 
larvse ; all the peculiarities of its structure are physiologically or teleologically intelligible 
only on this basis. Hunter, it is true, made his captive Sea-gull subsist wholly on 
grain f, and induced a Kite to eat and thrive on bread alone 
Save for loyalty to truth in the abstract one might be willing to accept the evi- 
dence adduced by Dr. Falconer § of the food given to captive Aye-ayes as proof of 
its being naturally a vegetable feeder ; but I believe the position of the mandibular 
condyles to be related to the powerful working of the pair of incisors. Such work is not 
needed for dividing the stems of rice or the stalks of dates or bananas. Nor are the 
Aye-aye’s conditions of condyle present in Hypsiprymnus or in any other vegetable feeder. 
No one can admit the Aye-aye to be a strict vegetarian who gives credit to the subjoined 
testimony : — 
“ It so happened that the thick sticks I now put into his cage were bored in all direc- 
tions by a large and destructive grub, called here the Moutouk. Just at sunset the 
Aye-aye crept from under his blanket, yawned, stretched, and betook himself to his tree, 
where his movements are lively and graceful, though by no means so quick as those of 
a Squirrel. Presently he came to one of the worm-eaten branches, which he began to 
examine most attentively ; and bending forward his ears, and applying his nose close to 
the bark, he rapidly tapped the surface with the curious second digit, as a Woodpecker 
taps a tree, though with much less noise, from time to time inserting the end of the 
slender finger into the worm-holes as a surgeon would a probe. At length he came to 
a part of the branch which evidently gave out an interesting sound, for he began to tear 
it with his strong teeth. He rapidly stripped off the bark, cut into the wood, and 
* X. p. 352; XI. p. 435. 
t Home, ‘Lectures on Comparative Anatomy,’ 4to, vol. i. p. 271. Owen, ‘Catalogue of the Physiological 
Series, Museum of the Royal College of Surgeons,’ 2nd ed. 8vo, p. 151, prep. no. 523. 
J Hunter, ‘Animal Economy,’ Owen’s Ed. 8vo, 1837, p. 112. 
§ X. p. 364 ; XI. p. 449. 
